To determine if your insert will fit you must look at the interior dimensions of the hood. We use 3/4″ thick material for the construction of the hoods. To determine the interior width you would look at the size hood you are interested in and subtract 1.5″. For example, for a 48″ hood (please note total exterior width for this option is 49.5″) the interior width would be 46.5″ wide. Then you must determine the interior depth. We have three options 18″, 20.5″ or 22.5″. Make sure to purchase the option that will best accommodate your insert. You must also look at height. The apron of all of our hoods is 8-1/4″ tall. If your insert is taller than this I would recommend reaching out to us directly so we can determine if it will work.